1. Field of the Invention
The invention relates to a device for regulating the tension of a moving web of material, in particular a web of paper in a paper-working machine such as a corrugating machine.
2. Background Art
A single facer for the manufacture of single-faced board is known from WO 00/00347, in which a liner and a medium are supplied to the unit for the manufacture of corrugated board. Prior to this, the liner is led around a cylinder, in the surface of which are provided numerous ports with water vapor exiting there-from for increased feeding of water into the liner. This arrangement is not capable of regulating and defining the tension of the liner web. Drawbacks of this arrangement further reside in that embodying the cylinder with corresponding steam passages is extraordinarily complicated. Moreover, quite a lot of vapor escapes unused in the peripheral areas of the cylinder that are not encircled by the liner web. Consequently, it is rather difficult, owing to this inaccuracy in the supply of water vapor, to pre-select and regulate the friction between the cylinder and liner web and thus the web tension that will result downstream of the cylinder.
It is an object of the invention to embody a device for regulating the tension of a moving web of material by which to regulate the web tension as precisely and in as simple a way as possible.
The object is attained in that the angle of contact a of the web of material on the first roller is modifiable by the at least one second roller being pivoted about the first roller. The gist of the invention resides in providing a first roller and at least a second roller that is mounted for pivoting about the first roller, with a web of material being passed around the first roller and the at least second roller. By the second outer roller being pivoted about the first inner roller, the angle of contact of the web of material on the first roller can be modified, and thus the friction between the web of material and the first roller. This helps affect the tension of the web of material downstream of the first roller.
Additional features and details of the invention will become apparent from the description of two exemplary embodiments, taken in conjunction with the drawing.